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clean up a comment a bit

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This commit is contained in:
JackDoan
2026-05-11 17:10:33 -05:00
parent 0ff28504d7
commit 3be637bade
1 changed files with 6 additions and 14 deletions
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20
interface.go
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@@ -285,7 +285,7 @@ func (f *Interface) activate() error {
// is on, everything else (and either lane disabled) falls // is on, everything else (and either lane disabled) falls
// through to passthrough so non-IP / non-TCP-UDP traffic still // through to passthrough so non-IP / non-TCP-UDP traffic still
// reaches the TUN. // reaches the TUN.
f.batchers[i] = batch.NewMultiCoalescer(f.readers[i], caps.TSO, caps.USO) f.batchers[i] = batch.NewMultiCoalescer(f.readers[i], f.l, caps.TSO, caps.USO)
} else { } else {
f.batchers[i] = batch.NewPassthrough(f.readers[i]) f.batchers[i] = batch.NewPassthrough(f.readers[i])
} }
@@ -372,18 +372,8 @@ func (f *Interface) listenOut(i int) {
} }
func (f *Interface) listenIn(reader tio.Queue, i int) { func (f *Interface) listenIn(reader tio.Queue, i int) {
// Pin this goroutine to one CPU. LockOSThread alone keeps the goroutine // Pinning this thread (and goroutine) to a single CPU keeps every sendmmsg from this goroutine going through the
// on a single OS thread but the kernel can still migrate that thread // same TX ring on the nic, so the wire sees per-flow order.
// across CPUs — XPS reads smp_processor_id() at sendmmsg time and picks
// the TX ring from the current CPU's xps_cpus map, so an unpinned
// thread bouncing between CPUs spreads one nebula flow's packets across
// multiple TX rings, which the rings then drain at independent rates
// and the wire delivers reordered.
//
// Pinning keeps every sendmmsg from this goroutine going through the
// same TX ring, so the wire sees per-flow order. Cost: less scheduler
// flexibility — if i % NumCPU collides between two TUN reader
// goroutines they share a CPU.
cpu := i % runtime.NumCPU() cpu := i % runtime.NumCPU()
if n := len(f.cpuAffinity); n > 0 { if n := len(f.cpuAffinity); n > 0 {
cpu = f.cpuAffinity[i%n] cpu = f.cpuAffinity[i%n]
@@ -391,8 +381,10 @@ func (f *Interface) listenIn(reader tio.Queue, i int) {
if err := util.PinThreadToCPU(cpu); err != nil { if err := util.PinThreadToCPU(cpu); err != nil {
f.l.Warn("failed to pin tun reader to CPU", "queue", i, "cpu", cpu, "err", err) f.l.Warn("failed to pin tun reader to CPU", "queue", i, "cpu", cpu, "err", err)
} }
rejectBuf := make([]byte, mtu) rejectBuf := make([]byte, mtu)
sb := batch.NewSendBatch(f.writers[i], batch.SendBatchCap, udp.MTU+32) arenaSize := batch.SendBatchCap * (udp.MTU + 32)
sb := batch.NewSendBatch(f.writers[i], batch.SendBatchCap, arenaSize)
fwPacket := &firewall.Packet{} fwPacket := &firewall.Packet{}
nb := make([]byte, 12, 12) nb := make([]byte, 12, 12)